U.S. Pat. Nos. 4,609,166 to Brennan and 5,154,374 to Beroth, incorporated herein in their entireties by this reference, disclose emergency oxygen-supply systems for aircraft. Included in the systems are oxygen-generating canisters located beneath seat cushions of commercial aircraft seats and oxygen masks positioned within the backs of the seats. Because the masks are positioned within seat backs, access to them is available only from the rears of the seats, so that the masks are intended for use only by passengers sitting in a row behind the seats in which the oxygen-generating canisters are located.
Detailed in U.S. Pat. No. 5,795,018 to Schumacher, et al. is an alternative oxygen-supply system for use in passenger cabins of aircraft. One version of the system includes a hollow, tubular bail associated with each passenger seat and at least partly framing its backrest. Incorporated in the bail is a head section containing, among other things, both an oxygen mask and an oxygen generator. Unlike the systems of the Brennan and Beroth patents, however, that of the Schumacher '018 patent is designed so that the oxygen mask resident in a particular head section is accessible to the passenger sitting in the associated seat.
U.S. Pat. No. 5,984,415 to Schumacher, et al. discusses cabin seats having passenger service units constructed as columns and arranged as “seat complementing components.” According to the Schumacher '415 patent, such a component is defined to mean “a separate service component independent of the seat but fully capable of cooperating with the respective passenger seat for the passenger's comfort.” See Schumacher '415, col. 2, 11. 55-58. Each component cooperates with a single seat to house, in a head section also functioning as a privacy shield, “essential passenger comfort and service elements such as a reading lamp, a loudspeaker or headphone jacks and an oxygen mask.” See id., col. 4, 11. 39-41 (numerals omitted). An oxygen generator is disposed within a lower section of the component below an armrest.
Whereas some embodiments of the columnar components of the Schumacher '415 patent provide mask access to the passenger seated in the seat associated with the component, other versions provide oxygen masks to passengers seated in a row behind the associated seats. Yet other embodiments of the Schumacher '415 patent incorporate oxygen masks and generators within arm rests of passenger seats. The contents of the Shumacher patents are incorporated in their entireties herein as well by this reference.
Generally, however, emergency passenger oxygen systems are located in passenger service units placed in overhead modules of commercial aircraft. Because so positioned, the service units must be configured to conform to spacing (pitch) between seat rows and the number of seats in a row so that each passenger has ready access to an oxygen mask when deployed for emergency use. This required matching of service units and seating arrangements complicates the design of seating configurations within a vehicle and makes modification of existing designs time consuming.
Further, because the service units are placed in overhead modules, lower cabin ceilings inevitably result from their use. These lower ceilings impede passenger ingress to and egress from respective seats and reduce the amount of headroom and storage space available to transiting passengers. As a consequence, at least some aircraft builders believe customer satisfaction is impacted negatively when overhead passenger service units are used.
Aircraft builders also have expressed interest in thinner seat designs. They thus may be reluctant to deploy some of the systems described above, in which oxygen-related equipment is incorporated into a seat back. Placing the equipment in the seat back additionally may be problematic for structural certification reasons and because of potential accessibility problems depending on whether, and if so how, the seat is reclined.